Phase-change materials (PCM) are capable of transforming from a crystalline phase to an amorphous phase. These two solid phases exhibit differences in electrical properties, and semiconductor devices can advantageously exploit these differences. Given the ever-increasing reliance on radio frequency (RF) communication, there is particular need for RF switching devices to exploit phase-change materials. However. the capability of phase-change materials for phase transformation depends heavily on how they are exposed to thermal energy and how they are allowed to release thermal energy. For example, in order to transform into an amorphous phase, phase-change materials may need to achieve temperatures of approximately seven hundred degrees Celsius (700° C.) or more, and may need to cool down within hundreds of nanoseconds.
In order to rapidly cool down phase-change materials, heat must be dissipated from a PCM RF switch by using heat spreading techniques. However, heat spreaders may pose manufacturing cost and device design challenges. Further, heat spreaders may result in increased RF noise coupling which can propagate across a semiconductor device and increase RF noise experienced by integrated passive devices (IPDs). Techniques for reducing RF noise coupling applicable to conventional semiconductor devices may not be suitable for PCM RF switches. Various modifications in structure can have significant impact on thermal energy management that decrease the reliability of PCM RF switches. Accordingly, integrating PCM RF switches with passive devices in the same semiconductor device can present significant challenges. Specialty manufacturing is often impractical, and large scale manufacturing generally trades practicality for the ability to control device characteristics.
Thus, there is a need in the art for semiconductor devices with improved heat dissipation for PCM RF switches and reduced RF noise coupling when PCM RF switches are integrated with passive devices in the same semiconductor device.